Vehicle Modifications

Buying a car is something that many of us do these days, as we become a society that relies on being able to travel freely. However, buying the car of our dreams is not always an option so people accept that they will have to make modifications to a car to bring it up to their expectations.

However, not all car modifications are legal and some are deemed as unnecessary. The problems occur when people modify their cars unlawfully like when they use big bore exhausts or heavily tinted windows. These are actually illegal in the UK and are classed as anti-social use of a vehicle.
When modifying your car there are some important issues to consider ensuring your vehicle is legal to drive on public roads.

The first thing to do when making any vehicle modifications is to inform your insurance company, whether you carry them out yourself or if the modifications were already installed when you purchased the vehicle. Failure to do so could seriously reduce any future claim you make and in a worst case scenario completely invalidate your insurance.

Secondly, you should be aware that modifying your car will make it more attractive to thieves and that you should take every precaution when securing your vehicle.

If you are thinking of modifying your vehicle, you need to check if the modifications are acceptable under the Road Traffic Act.

Any vehicle modifications that you make to your car should be carried out by someone who knows what they are doing, preferable a licensed dealer to ensure that your car remains road worthy.


The vast majority of large or big bore exhausts are illegal for use on public roads. The fact they may have passed an MOT test is irrelevant as this only checks for exhaust gasses and emission legislation compliance.

Big bore and sports exhaust systems are usually fitted to increase the sound emitted and this contravenes the Type Approval of the vehicle, which is an offence.

There is no requirement for police to measure the sound level from the exhaust system, it only requires an opinion that the system is not standard and that it is noisier than a normal vehicle of the same specification.

It is not an offence to sell these exhaust systems, but it is an offence to fit one to your vehicle and drive it on a public road. Motorists who do so would be reported to court and may face a fine and court costs.

Tinted windows

Heavily-tinted windows will seriously reduce your view in certain weather conditions and most definitely at night time.

The legal requirements allowed are 75 per cent of light through the front windscreen and 70 per cent of light through the side window on the front doors. Any rear door glass and rear windows are not included in this requirement so they can be as heavily tinted as you like.

We do have instruments which can now measure the severity of a tinted window. If a window is found to be too heavily tinted the motorist could be subject to a Fixed Penalty Notice or reported to court.

Lighting offences

Blue lights: The law states that only emergency vehicles can display blue lights so it is an offence if your vehicle has any LED or neon under-vehicle lighting system or lights on windscreen, washer jets or number plates emitting a blue light. The motorist could receive a Fixed Penalty Notice and or be reported to court.

Fog lights: For vehicles fitted with front fog lights (rear fog lights are also included), it is an offence to illuminate them unless visibility is seriously reduced, which is defined as driving in rain, snow or fog with visibility less than 100 metres. Fog lights cause dazzle to other drivers and can attract a Fixed Penalty Notice.

Other lights:

It's an offence to show a red light to the front of a vehicle (including a reflector) and a white light to the rear unless reversing. Once again these offences are dealt with by means of a Fixed Penalty Notice. It does not matter if the lights are mounted inside or outside the vehicle, just that the light can be seen from the outside. This would also include neon lights fitted under or on the side of a vehicle and red LED windscreen washer jets. Green lights can only be fitted on Medical Practitioners vehicles.

Number plates

Number plates must conform to current requirements in relation to size in terms of the number plate itself and the characters, spacing, format and font.

You must not misrepresent the characters either, for example by spacing them to make up a word or name or by strategically placing fixing screw covers to alter any character. Fonts including italic, bold and shadow are all illegal.

Number plates must be white reflective to the front and yellow reflective to the rear and the characters have to be black. The exception to this rule is if the vehicle (note: the legislation states vehicle not the number plate itself) is registered prior to 31 December 1972, in which case black and silver number plates can be fitted front and rear.

If the number plates on the vehicle do not comply with the above legislation this could result in a Fixed Penalty Notice being issued and/or the DVLA being notified of the offence. Ultimately, the DVLA can withdraw the number plate from the vehicle temporarily or permanently, even though you pay for them. The DVLA still own the plate, you are just given the privilege of displaying them on a vehicle.

Section 59 of the Police Reform Act – Anti Social Driving Offences

New laws in respect of certain anti social driving offences can now be dealt with by Section 59 of the Police Reform Act.

Basically what that means is if you are seen:

Driving in a careless or inconsiderate manner

Driving on common land, a footpath or bridle way or any land which is not part of a road

Driving in a manner which is causing/has been causing, or is likely to cause alarm, distress or annoyance to members of the public.

Then a Section 59 warning can be issued to you. This warning is placed against both the driver and the vehicle and lasts for 12 months.

If the driver of the vehicle or the vehicle with the warning issued to it is then seen driving in any of those conditions again in the next 12 months the vehicle can be seized and, if not collected after paying for recovery and storage costs, it will be crushed. Please note that this relates to either the driver with the Section 59 or the vehicle.